Anti-offset roll



March 1967 J. v. MILLER 3,308,522

ANTIOFFSEI' ROLL Filed Dec. 14, 1962 United States Patent 3,308,522 ANTI-OFFSET ROLL James V. Miller, Chicago, 111., assignor, by mesne assignments, to Velcro Corporation, New York, N.Y., a corporation of elaware Filed ec. 14, 1962, Ser. No. 244,668 13 Claims. (Cl. 29-120) The present invention relates to rolls such as guide rolls or idler rolls used in printing presses, coating machines and the like, for supporting or guiding a freshly printed or coated web of paper or other material by contact with the freshly printed or coated surface of such web. Such rolls are frequently used between successive printing units of web presses which print first one side and then the other side of a web, or which apply different colors successively to one surface of the web. Similarly, in coating machines it is frequently necessary to support or guide a web by contact with the freshly coated surface thereof as it progresses toward a dryer or other further processing device. To prevent or reduce transfer of undried ink or coating material to the guide roll and also to prevent or reduce marking or smearing of the printed or coated surface, so-called anti-offset guide rolls of various constructions have been used or proposed.

The present invention provides anti-offset rolls of the general type just referred to which present for contact with the freshly printed or coated surface of the web, a large number of pile-like protuberances which, while relatively stiff, are nevertheless somewhat springy and have very small areas for contact with the inks or coating materials on the webs. The protuberances preferably are of uniform height and are uniformly spaced rather sparsely over the surface of the roll. The protuberances preferably are formed as pile elements extending generally vertically from a flexible sheet of base material which is secured to the cylindrical surface of the roll. A preferred form of the present invention makes use of a fabric base sheet having pile elements formed integrally therewith, as by weaving, molding and the like. The pile elements, because of their resilience, permit the adjustment of web tension to such values as to insure accuracy of register without the danger of rupturing of the web which exists when non-yielding anti-offset devices are used. Also, they are easier to clean and offer much less likelihood of injury to operators than the abrasive coated or punched sheet metal covered rolls currently in use in many places.

In a specifically preferred form of the present invention the anti-offset roll is covered by spirally wrapping and adhesively securing to the cylindrical surface of the body of the roll, an elongated ribbon comprising a base fabric woven from a synthetic material such as nylon with a pile formed from nylon monofilament, the pile having been heat-set after weaving of the ribbon to enhance the tendency of each pile element to stand substantially vertically relative to the base fabric and to spring back to such vertical position after deflection. Also preferably, the woven base fabric of the ribbon is impregnated with some suitably inert durable material which may be dried or set or heat-set within the interstices of the woven fabric base to render the same impervious to the ink or coating material and appropriate cleaning solvents to which the material may be exposed. For instance, a woven nylon base fabric as discussed above may be impregnated with polyurethane. Instead of spiral wrapping of a ribbon of material as just described, the rollers of the present invention may be covered or jacketed with a relatively wide web of woven fabric having resilient heat-set pile elements such as those described above. 7

It is an object of the present invention to provide antioffset rolls for printing and coating machines and the like, which support or guide a web by contact with a large number of flexible, resilient, pile-like protuberances distributed over the surfaces of such rolls.

Other and further objects and advantages of the present invention will become apparent from the following description of preferred, but not necessarily the only, forms of the present invention, taken in connection with the accompanying drawings.

In the drawings:

FIG. 1 is a diagrammatic illustration of a typical printing or coating apparatus in which an anti-offset roll embodying the present invention is illustrated;

FIG. 2 is a front elevation of an anti-offset roll embodying the present invention and illustrating one manner in which the roll covering may be applied;

FIG. 3 is a fragmentary somewhat diagrammatic and enlarged sectional view taken along the line 3-3 in FIG. 2;

FIG. 4 is a fragmentary somewhat diagrammatic and greatly enlarged perspective view of one form of covering material for anti-offset rolls embodying the present invention;

FIG. 5 is a view similar to FIG. 4 but showing a different form of covering material; and

FIG. 6 is a view similar to FIG. 4 but showing still another form of covering material.

Referring now to the drawings, the anti-offset roll of the present invention is illustrated in FIG. 1 in a typical association with a printing or coating apparatus which comprises a printing or coating roll 10 and a tympan or backing roll 12. A web 14 of paper, or other web material which is to be printed upon or coated, passes between the rolls 10 and 12 for the application thereto by the roll 10 of a continuous or discontinuous film of ink or coating material. The web 14 continues around the roll 12 with the freshly printed or coated surface of the web facing downwardly as viewed in FIG. 1, and the latter surface is then conducted over a roll 16 which serves to guide the web 14 into the direction indicated by the arrow 17. The roll 16 is illustrated in FIG. 1 in a po sition in which anti-offset rolls are typically used. It will be understood that the roll 16 may be an idler roll or that it may be driven as may be desired. In accordance with the present invention a roll such as the roll 16 shown herein is rovided with a covering material 18 secured to the cylindrical surface thereof which affords unique offset-preventing characteristics.

As shown in FIG. 2, the covering material 18 may be applied to the roll 16 in the form of a relatively narrow ribbon which is wound spirally upon the cylindrical surface of the roll 16 throughout the width thereof, or at least throughout such portion of the width thereof as may be expected to come into contact with a freshly printed or coated web. As will be discussed further herernbelow, the ribbon 18 may be wound as a continuous spiral as illustrated in FIG. 2, or alternatively may be wound in two spirals extending respectively from the opposlte ends of the roller 16 toward the center thereof to provide spirals of opposite hand having a tendency to transversely spread the web. In either event the ribbon 18 of covering material may be secured to the cylindrical surface of the roll 16 by a suitable adhesive and the adjacent turns within the spiral or spirals are preferably arranged to he closely together so as to present a relatively contmuous surface, the seams of which extend angularly to the path of travel of the freshly printed or coated web 14.

Referring now to FIG. 3, the cylindrical body of the roll 16 may be made of any suitable material and may be solid or tubular. For example, it may be made of metal, wood or plastic, or composites thereof as may be desired. The covering material 18 comprises a base sheet 20 and a plurality of generally vertically disposed protuberances 22. The protuberances 22 preferably are of uniform height and preferably are uniformly spaced throughout the surface of the base sheet 20 of the covering material 18. Since the protuberances 22 extend sub stantially vertically from the base sheet 20 it will be apparent that when the covering material 18 is secured to the cylindrical surface of a roll 16 each of such protuberances will extend substantially radially outwardly of the roll 16.

FIG. 4 illustrates, somewhat diagrammatically and enlarged, a fragment of one form of covering material 18 which may be employed as illustrated in FIGS. 1, 2 and 3. In FIG. 4 the base sheet 20 consistsrof a woven textile fabric and the protuberances 22 are in the form of pile loops which are quite uniformly although sparsely spaced upon the upper surface of said base fabric. The lower surface of the base fabric 20 is relatively smooth. A loop pile fabric of the type shown in FIG. 4 may be woven in a ribbon loom having suitable pile wires or lancets over which special he'at-settable warp yarns are thrown in a known manner to form the pile loops. It is important in connection with the present invention that the pile loops be held upright as the ribbon emerges from the loom until such time as the pile may be subjected to heat treatment for setting each pile loop in upright position. The weaving of the ribbon and the heat-setting of the pile loops may be accomplished on apparatus as disclosed in US. Patent No. 3,009,235 to De Mestral, wherein the pile Wires or lancets extend forwardly from the loom for a distance sufiicient to permit heat-setting of the pile loops by suitable heating apparatus positioned above the pile wires or lancets.

It is preferred for the purposes of the present invention, to weave the ribbon 18 from a heat-settable synthetic material such as nylon, which may be used as the yarns incorporated into the base fabric 22 in the form of multifilament or staple fiber structures and which may be used for the pile loops 22 in the form of monofilaments of relatively heavy denier. When nylon or other suitable heat-settable synthetic material is used in both the base fabric and the pile, the heat-setting operation referred to above may be effective not only to set the pile loops 22, but also to set the yarns in the base sheet 20 in their woven positions, thus to impart great stability and strength to the final product.

In FIG. 5 the covering material 118 may be identical with the material 18, just described in connection with FIG. 4, except that each of the pile loops has been cut to form a hook 122 and relatively short stub 123. Ma.- terials of this particular type are available on the market, being sold inthe form of ribbons of various widths under the trademark Velcro by Velcro Corporation, 681 5th Avenue, New York, N.Y., and they are widely used as separable fastener elements. Since one leg of each pile loop has been cut the hooks 122 ofier less resistance to temporary deformation than would be offered by unout loops of the same material.

In FIG. 6 the covering material 218 may be identical with the material 18 described in connection with FIG. 4, except that each of the pile loops has been sheared off to leave two generally vertically extending piles 222 and 223. While, as shown, the entire curved upper portion of each loop has been sheared off, it is not essential that this be true. For the purposes of the present invention the pile loops may be sheared at a level higher than is customary with decorative fabrics, thus leaving a curved upper end portion on each separated pile element 222 and 223. The sheared pile elements 222 and 223 will each present a very small area for contact with the freshly printed or coated web when the material 218 is used as a covering for an anti-offset roll body of the type shown at 16 in FIG. 1.

The materials 18, 118 and 218 respectively may be used in the form of ribbons and may be applied spirally to a roll body 16 as illustrated in FIG. 2. Ribbons having a width of about two inches are convenient to handle, although narrower or wider ribbons may be preferred, depending, among other things, upon the dimensions of the roll body to which they are to be applied. With Very Wide ribbons a single spiral turn may sufiice to cover a roll of appropriate dimensions. In other instances the materials 18, 118 and 218 may be sufiiciently wide to cover a roll in a single convolute turn with an appropriate straight or angled butt point as may be desired.

Any of the materials 18, 118 or 218 are constructed in such manner that the pile elements 22, 122 or 222 will hold the freshly printed or coated web 14 out of contact with the base fabric 20, or 220. Preferably, a substantial amount of clearance is provided between the web and the 'base fabrics in order that a considerable amount of accumulated ink or coating material may lie upon the base fabric out of contact with the web. If and when any such accumulation threatens contact with the Web it may be removed by cleaning as will be described below. In selecting the height of the pile for the purpose just mentioned, it may be necessary to take into account the flexibility of the pile elements in the event there is to be a substantial amount of tension upon the web. For use in a multi-color web-press printing on newsprint very satisfactory results have been achieved with a roll covering material having uncut pile loops approximately in height spaced thirteen per inch in the direction of rotation of the roll and spaced twenty per inch transversely thereof. The loops were formed from strands of nylon monofilament having a diameter of about 0.008.

The covering materials of the present invention preferably are impregnated or coated with a suitable material to add to the stability of the weave and which will render the woven base fabric impervious to selected liquids. Preferably, for the purposes of the present invention, the

impregnating or coating material is one such as nylon or a polyurethane which is substantially inert to water, petroleum solvents and other materials commonly used as vehicles in or cleaning fluids for the removal of printing inks or coating compositions. Suitable impregnating or coating material may be applied to the ribbon prior to heat-setting in which event the applied material may be heat-settable at temperatures compatible with the heatsetting temperature of the nylon or other material from which the pile loops are made. A wide variety of impregnating or coating materials may be used when the same are applied to the ribbon after heat-setting, and such impregnating materials may themselves be set by heat or chemical activation or they may be of such nature as to solidify by solvent evaporation.

The covering materials or ribbons 18, 118 and 218 may be adhered to the surface of the roll 16 by the application to the roll surface or to the back of the material or both, of a suitable adhesive. For convenience in use it is preferred to apply a layer 19, 119 or 219 to the base fabrics 20, 120 and 220 respectively, of an adhesive material which may be dried to form a precoat on the material as sold to the user. The precoat may be activated by the application thereto of a suitable solvent 'for the precoat at the time of application of the ribbon to the roll 16. For example, the precoat on a nylon base fabric impregnated with polyurethane may comprise a synthetic rubber resin which is dried to non-tacky condition for shipment and handling of the ribbon. At the time of application thereof to a roll 16 having a smooth metal surface, for example, an activator such as methyl-ethyl-ketone (MEK) may be applied to the precoat layer 19, 119 or 219 Whereby it becomes tacky and will adhere with great tenacity to the metal surf-ace. The adhesive bond thus formed will be unaffected by almost any type of ink, coating material or cleaning solvent in normal use. In other instances, a water-sensitive precoat may be used, particularly where no water-based inks or coating materials or cleaning solvents are to be used, or a petroleum solventsensitive precoat may be used where water-based inks, coating materials and solvents only are to be used.

As a matter of convenience it is preferred to use a relatively fast setting adhesive material and to apply it or to activate it, in the event a precoat of adhesive is used in relatively small areas in a progressive fashion as covering of the roll proceeds. This is particularly helpful when a relatively narrow ribbon of covering material 18, 118 or 218 is to be applied in the form of a spiral as shown in FIG. 2, or in the form of two oppositely-handed spirals as discussed above.

The anti-offset rolls of the present invention afford a number of advantages over the several most popular types of anti-offset rolls now in use. The latter includes cheesecloth wrapped rolls, abrasive particle coated rolls, glass bead coated rolls, rolls made up of a plurality of serrated discs and rolls covered with thin sheet metal having teeth punched outwardly like a nutmeg grater. The cheesecloth wrapped rolls normally have alarge number of convolute turns of cloth, the outer few layers of which are expected to absorb some portion of the undried ink or coating material without smearing for a short time after which the outer turns are stripped ofl? to expose unsaturated lower turns. This requires frequent shut-down at best and is not at all satisfactory in connection with relatively wet inks or coatings. The other types of rollls listed above, except for the expensive serrated discs, have web contacting elements which are not basically uniform in size and, even when the particles or beads are carefully selected, must be so closely packed upon the roll surface as to afford little room for accumulation of ink or coating composition. The closely packed particles or beads present relatively few contact points which lie precisely within the plane of the web surface, and the many which do not engage the web merely take up space. All of the rolls wit-h rigid elements such as particles, beads or teeth are dangerous to persons operating the equipment. Cleaning of some of these rolls is very diflicult and sometimes hazardous. The punched sheet metal presents hollow teeth of somewhat irregular heights and the punched openings receive ink or coating material which is held within the hollow teeth to bleed upon subsequent portions of the web and where it is substantially impossible to remove by cleaning. Except for the cheesecloth covered rolls there is no cushioning effect or yieldability afforded by any of the anti-offset rolls of the types just discussed.

The anti-offset rolls of the present invention afford protuberances 22, 122, 222 which are pile elements substantially uniform in height and which, because of their individual springiness, will adjust themselves into individual contact with the web to compensate for such minor irregularities in height as may exist. Therefore, since substantially all of such protuberances may be depended upon to engage the web they may be spaced laterally from each other sufficiently to minimize surface-tension accumulation of undried ink or coating material between the protuberances. Also, since the diameter or other maximum cross-sectional dimension of the strands from which such pile elements are formed is a relatively small fraction of the length of each element and of the lateral distance between adjacent elements, the elements themselves occupy only a small portion of the total volume of the space between the web 14 and the outer surface of the roll covering material 18, 118 or 218. This leaves a large and very uniformly distributed unoccupied volume for the accumulation of such ink or coating material as may flow from the web. Any such accumulation may be removed by brushing, with or without a cleaning agent or solvent, and the bristles of the cleaning brush cannot become entangled with or damage the yieldable springy pile elements 22, 122 or 222.

It will be recognized that the monofilament pile elements 22, 122 or 222 made of nylon or other suitable synthetic material are non-absorptive of liquids-and differ in this respect from the absorptive natural fibers or absorptive synthetic fiber yarn structures, such as multifilament or staple fiber yarns, heretofore used in the manufacture of paint rollers or other applicator rollers which are sometimes covered with textile materials. Similarly, the relatively sparse distribution of the pile elements 22, 122 and 222 in the anti-offset rolls of the present invention affords no opportunity for surface-tension accumulation or adsorption of liquids between adjacent pile elements, and this is in contrast with the closely piled fabrics or thickly bristled brush elements used as applicators in painting or coating operations.

What is claimed is:

1. A guide roller for engagement with the undried coated or printed surface of a moving web and for minimizing transfer of undried coating material from said web to said roller, said roller comprising a cylindrical body and covering material attached to the circumferen tial surface of said body, said covering material comprising a base sheet having attached thereto a multitude of pile element projections sparsely distributed over .a substantial portion of its outer surface and extending generally normal thereto, each of said pile elements being a strand of fiber made of a non-absorbent material which is substantially inert to said undried coating material and having one of its ends engaged in the base sheet, the length of the element and the lateral spacing between adjacent elements being substantially greater than the maximum cross-sectional dimension of the fiber, and each projection being flexible and tending to resiliently return to its normal position when deflected.

2. A guide roller according to claim 1 wherein each of said pile elements is made from a nylon monofilament.

3. A guide roller according to claim 1 wherein said base sheet is a woven fabric and said pile elements are formed from strands woven into said fabric.

4. A guide roller according to claim 1 wherein said covering material is in the form of a ribbon wound helically or spirally upon and secured to the outer surface of said cylindrical body by an adhesive.

5. A guide roller according to claim 1 wherein said base sheet is a woven fabric, the interstices thereof being impregnated with a plastic substance to render said base sheet impervious to and substantially inert to said undried surfacing material.

6. A guide roller according to claim 1 wherein said base sheet is a fabric woven from nylon yarns and said pile elements are formed from nylon monofilaments woven into said fabric.

7. A guide roller according to claim 1 wherein said base sheet is impregnated wit-h polyurethane.

8. A guide roller according to claim 1 wherein each of said projections comprises a strand of fiber formed in a closed loop with its legs remote from the closed part being engaged in the base sheet.

9. A guide roller according to claim 8 wherein each of said projections comprises a hook part and an adjacent stem part formed from a loop element having a portion of one of the legs of the loop removed, the ends of the legs remote from the closed part of the loop being engaged in the base sheet.

10. A guide roller according to claim 1 wherein there is uniform lateral spacing between adjacent projections.

11. A guide roller according to claim 1 wherein there is uniform height of the projections.

12. A guide roller according to claim 1 wherein the projections consists of pile elements made of a thermosetting synthetic (fiber material.

13. A guide roller according to claim 1 wherein the strand of each projection forms a pair of stems, one end of each stem being attached to the base sheet, the opposite ends of the stems spaced from each other and extending from the base sheet.

(References on following page) References Cited by the Examiner UNITED STATES PATENTS Morrow 118-224 McCollum 29-120 Newcomb 101-420 Melton et a1. 101-420 8 TisCher 29-120 Cross 101-420 Fleischauer 29-120 Gutweniger 101-420 MORRIS KAPLAN, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No., 3,308,522 March 14, 1967 James V. Miller It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 28, for "5/54"" read 5/64""; column 6, line 56, for the claim reference numeral "8" read l --o Signed and sealed this 7th day of November 1967 (SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

1. A GUIDE ROLLER FOR ENGAGEMENT WITH THE UNDRIED COATED OR PRINTED SURFACE OF A MOVING WEB AND FOR MINIMIZING TRANSFER OF UNDRIED COATING MATERIAL FROM SAID WEB TO SAID ROLLER, SAID ROLLER COMPRISING A CYLINDRICAL BODY AND COVERING MATERIAL ATTACHED TO THE CIRCUMFERENTIAL SURFACE OF SAID BODY, SAID COVERING MATERIAL COMPRISING A BASE SHEET HAVING ATTACHED THERETO A MULTITUDE OF PILE ELEMENT PROJECTIONS SPARSELY DISTRIBUTED OVER A SUBSTANTIAL PORTION OF ITS OUTER SURFACE AND EXTENDING GENERALLY NORMAL THERETO, EACH OF SAID PILE ELEMENTS BEING A STRAND OF FIBER MADE OF A NON-ABSORBENT MATERIAL WHICH IS SUBSTANTIALLY INERT TO SAID UNDRIED COATING MATERIAL AND HAVING ONE OF ITS ENDS ENGAGED IN THE BASE SHEET, THE LENGTH OF THE ELEMENT AND THE LATERAL SPACING BETWEEN ADJACENT ELEMENTS BEING SUBSTANTIALLY GREATER THAN THE MAXIMUM CROSS-SECTIONAL DIMENSION OF THE FIBER, AND EACH PROJECTION BEING FLEXIBLE AND TENDING TO RESILIENTLY RETURN TO ITS NORMAL POSITION WHEN DEFLECTED. 